(New York Times, Dec. 18; https://www.nytimes.com/2018/12/18/opinion/climate-carbon-tax-innovation.html) Senator John Barrasso astonishingly stated “Nuclear energy is produced with zero carbon emissions.”
As chairman of the Environment and Public Works Committee and member of the Energy and Natural Resources Committee, he will have access both to expert committee advisors as well as the erudite staff of the Library of Congress.
Had he consulted either, he would have been told production of nuclear electricity is not carbon free, because the production of nuclear fuel for these reactors is significantly energy intensive.
While it is true that most nuclear reactors do not emit CO2 at the point of generation, reactors are a small part of the nuclear fuel cycle, which emits large amounts of CO2.
These arise from the so-called front end of the fuel cycle - uranium mining, ore milling, uranium hexafluoride conversion, fuel enrichment and, finally, fabrication of the fuel rods. Moreover, nuclear waste management at the "back end" is already energy hungry in treatment, conditioning, transportation and final disposal in some future repository (if Congress ever give the green light).
Thus life-cycle analyses are essential to assess the true impact of the entire processes.
A number of such studies have examined CO2 emissions - commonly expressed as CO2 equivalents per kWh - for different methods of producing electricity. The most comprehensive model has been created by the Öko Institut, which advises the German environment ministry, and by Professors Smith and Van Leeuwen at the University of Groningen, in the Netherlands.
Öko's analysis shows that nuclear CO2 emissions are up to four or five times greater than those from renewables.